In-Key Features:1. FILTER MORE: Filters up to 4000 liters of natural fresh water without using any chemicals. 4000L clean and drinkable water in a backpack on the go.2. VERSATILE DESIGN: Easily set up a DIY filtration system by soda bottle like Coca-Cola bottle, plastic bag, collapsible bottle or bucket. Or drink directly from water source like a straw.3. BACKFLUSHING WITH EASE: Threads on filter both sides. A handy 28mm threads bottle can be screwed on water filter outlet for backwashing.4. Reliable filtering result: 0.1 micron membrane ensures 99.999999% removal rate of bacteria. TUV and SGS testing reports.5. Superior material: FDA approved. Impact resistance and ultra-light L630 fits in the palm of your hand. Lifespan can be extended by backwash.Good choice for camping, hiking, fishing, scouting, travel, military, survival use, or emergence supplies.